Easy-open container end with reinforcing bead



Aug. 20, 1968 R. L. BATCHELAR EASY'OPEN CONTAINER END WITH REINFORCING BEAD Filed June 26, 1967 INVENTOR. KA YMflA fi Mam/vii Mid/[214R United States Patent 3,397,812 EASY-OPEN CONTAINER END WITH REINFORCING BEAD Raymond Luscombe Batchelar, Westwood, N.J., assrgnor to American Can Company, New York, N.Y., a corporation of New Jersey Filed June 26, 1967, Ser. No. 648,649 Claims. (Cl. 220-54) ABSTRACT OF THE DISCLOSURE In a container end closure or other component having a scored tear-out section with a drawn, integral rivet securing a lifting lever to said section, a bead in the end closure is disposed in such encircling proximity to the rivet as to stiffen the unstable metal of the end closure about the rivet to preclude inadvertent reverse flexing of such metal, thereby rendering a score line adjacent said rivet abuse-resistant.

Background of the invention This invention relates in general to containers of the easy-opening type and more particularly to a metal end closure having a manually removable tear-out area set off by a score line.

Heretofore, in easy-open container ends of the type wherein a lift lever is secured to a tear-out section by means of a drawn rivet, it has been found that the score line in the area around the rivet frequently was inadvertently fractured because of flexing of the metal adjacent the rivet. The flexing, which occurred because of pressures which were inadvertently exerted on the rivet during handling and shipment, was due to the formation of a shallow flexible dome around the rivet and to the presence of excess metal which was introduced into portions of this dome during the rivet-forming and endscoring operations. To avoid this inadvertent flexing and the resultant fracturing of the score line in the area around the rivet during normal use, means are provided, according to the present invention, to stiffen or rigidify the dome and to take up the excess metal therein.

Summary of the invention A metal end closure for a container is provided with a tear strip set off by score lines, and with a drawn rivet, integral with the end closure, which secures a lift lever to the tear strip. The rivet is surrounded by a shallow dome which is produced in the rivet-forming operation. One of the score lines has a portion extending partially about the rivet and through the shallow dome to define the starting end for the tear strip. A bead in the panel extends partially about the rivet around the base of the dome to stiffen the dome and accommodate excess metal in it, thereby to preclude reverse flexing of the dome and thus prevent inadvertent rupture of the score line portion therein.

Brief description of the drawing FIGURE 1 is a plan view of a container end closure embodying principles of the present invention.

FIGURE 2 is an enlarged partial sectional view taken along a line corresponding to the line 33 of FIGURE 1, but showing the end as it exists during an intermediate stage of manufacture.

FIGURE 3 is a partial sectional view taken substantially along the line 33 in FIGURE 1.

Description of the preferred embodiment In the illustrated embodiment there is shown a metal (e.g. aluminum, tin plate) container end of the easyopen type. The end 10 is adapted to be doubleseamed or "ice otherwise afiixed to the longitudinal end of .a cylindrical container body (not shown) in a manner well-known to those skilled in the art. The end 10 has a conventional hooked flange 12 to facilitate the doubleseaming.

The illustrated end has an annular reinforcing groove 14 which circumscribes a circular panel 16, substantially all of which is removable to provide access to the contents of the container. To provide for such removal, there is provided in the end panel 16 an outer score line 20 extending entirely around its periphery and an inner score line 22 which extends adjacent to and is spaced from the outer score line 20 for a major portion of the length thereof. The score lines 20 and 22 cooperate to define therebetween a tear strip 24 having a starting end 26, the latter being defined by a portion 22a of the inner score line 22 which makes an approximately degree turn to join the outer score line 20 as shown in FIGURE 1.

The inner score line 22 preferably does not make a complete circle of the end panel but terminates in a short, inwardly turned portion 28. Accordingly, the tear strip 24 does not extend entirely around the tear-out end panel 16 but, rather, terminates at 28, short of a terminal end section 20a of the outer score line 20. Thus, after a major separation of the tear-out panel 16 from the remainder of the end by means of the tear strip 24, the entire panel 16, defined by the outer score line 20, is separated as a unit from the remainder of the end 10 by the continued rupture or tearing along the terminal section 20a of the outer score line 20.

The starting end 26 of the tear strip 24 is provided with a substantially rigid lift lever or pull tab 30 to facilitate tearing and removal of the tear-out panel 16. The pull tab 30 may be of any configuration and is secured to the panel 16 by means of a peened-over embossment or rivet 32 which is integral with and drawn from the metal of the end panel 16, the rivet 32 extending upwardly through an aperture in the pull tab 30 and having its upper end peened outwardly to secure the tab 30 in place. A suitable method for forming the rivet 32 is disclosed in United States Letters Patent 3,191,564, granted June 29, 1965.

In ends as heretofore produced, the end panel metal around the rivet 32 has been unstable and subject to inadvertent flexing because of the rivet-forming and the scoring operations. Thus, the drawing operations which are required to create the rivet 32 cause a thinning of the metal in the area of the end panel immediately surrounding the rivet 32 (e.g. in the circular portion generally bounded by reference circle A), and also cause it to bulge upwardly from the plane of the end panel 16 to form a shallow dome 34 which is inherently unstable and subject to reverse flexing, otherwise known as flipping. This instability is enhanced by the formation of the score line portion 22a, since the metal which is displaced from this score line is caused to flow laterally into the adjacent metal of the dome 34, where it becomes excess metal. The result is that there is distribution of excess metal in portions of the dome 34 which further increases its tendency to reversely flex inwardly to the position indicated by the dot-and-dash line 34F in FIGURE 2, which figure shows the end during an intermediate stage of manufacture after the rivet drawing and the end-scoring operations have been completed, but before the lift tab has been secured in place. The dome profile in this FIGURE 2 corresponds to the profile of finished prior art ends. The reverse flexing of the dome of such prior art ends tends to occur during shipment and handling when pressure is inadvertently applied against the top of the rivet 32. If this flexing occurs with sufficient frequency the possibility of premature inad vertent rupture of the scoreline section 22a around the rivet 32 is substantial.

According to the present invention, this excess metal is taken up, and the area adjacent the rivet 32 is stiffened or rigidified, by employment of an arcuate bead 36 extending partially around the rivet 32 and preferably located inwardly of the base line A of the dome 34, although under certain circumstances it may be on or slightly outwardly of the base line A.

This bead 36 is preferably indented into the metal of the end and, in effect, provides a sharply defined base portion for the dome 34 and functions to deepen the dome and to decrease its diameter. It also decreases the radius of curvature of the dome, at least in its peripheral portions. All of these effects stiffen the dome 34 and greatly increase its resistance to reverse flexing. In addition, the bead 36 also functions to absorb the excess metal which has been created in portions of the dome 34 as a result of the formation of the score portion 22a, which excess metal would otherwise tend to cause warping of the dome and increase its instability and tendency to flip.

It will be noted that the head 36 does not form a complete circle but, instead, extends for only somewhat more than 180 of are so that, in general, it parallels the score 22a. As a result, the open mouth of the bead is positioned so that it straddles the score portion 22a. By virtue of this arrangement, the bead 36 does not cross the score line portion 22a. One advantage of this construction is that it minimizes the possibility of inadvertent rupture of the score line during the formation of the head 36, which formation preferably takes place concurrently with or subsequent to the scoring operation in order to have the bead absorb the excess metal which flows from the score line portion 22a. Another advantage is that it prevents possible interference with the tearing of the score portion 22a by the head during the end-opening operation. It has been found that the arcuate bead 36 functions efliciently to prevent flipping of the dome 34 even though it does not comprise a complete circle, and that the elimination of this flipping has resulted in the substantial elimination in inadvertent premature rupture of the score line portion 22a in the dome 34, which rupture was a serious problem prior to this invention.

It will be understood that the bead may have other configurations, the arcuate bead 36 being illustrative, as long as the bead is effective to rigidify the domed area adjacent the rivet 32 and to take up excess metal therein. Further, it will be understood that the tear strip 24 4 shown in the drawing is merely illustrative and that various other easy-opening tear strips or tabs may be used in connection with this invention. For example, the principles of the invention are equally applicable to limited access tear strips of the type commonly used on cans holding liquids, for example, beer, carbonated beverages and the like.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a metal container component of the type comprising a panel, a lift lever, a drawn rivet integral with said panel and securing the lever to said panel, a shallow circular dome surrounding said rivet, and a score line setting off a removable area in said panel, a portion of said score line being located in said dome and extending partially about said rivet to define a starting end for the removable area, the improvement which comprises a bead formed in said panel adjacent the base of said dome to stiffen said dome and to absorb the excess metal which is forced into portions of said dome during the formation of said score-line portion therein, whereby inadvertent flexing of said dome and the resultant rupture of the score-line portion in said dome is prevented.

2. A metal end closure according to claim 1 wherein said head is formed as a depression in said panel.

3. A metal end closure according to claim 1 wherein said bead has a generally arcuate configuration.

4. A metal end closure according to claim 2 wherein said bead does not extend across the score-line portion in said dome.

5. A metal end closure according to claim 1 wherein said bead at least partially underlies said lift lever.

References Cited UNITED STATES PATENTS 5/1966 Fraze 220-54 1/1967 Pugh 220-54 

